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STMicroelectronics ACS108-8SA
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- Part No.:
- ACS108-8SA
- Manufacturer:
- STMicroelectronics
- Category:
- TRIACs
- Package:
- TO-226-3, TO-92-3 (TO-226AA)
- Datasheet:
-
ACS108-8SA.pdf
- Description:
- TRIAC SENS GATE 800V 0.45A TO92
- Quantity:
- Payment:
- Shipping:
Inventory:2,437
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Product details
Overview
ACS108-8SA from STMicroelectronics is a single-pole, 800 V blocking, 0.8 A RMS overvoltage-protected AC switch (ACS™) with integrated crowbar clamping and gate-level shifter. It operates in quadrants II and III, triggers via negative gate current (≤10 mA), and withstands 2 kV IEC 61000-4-5 surges without external snubbers-enabling direct microcontroller interfacing in appliance motor control.
For engineers reviewing the ACS108-8SA datasheet, ACS108-8SA pinout, ACS108-8SA application, or ACS108-8SA equivalent, this device is selected for robust AC load switching where dV/dt immunity (>2000 V/μs at 125 °C), VCL clamping (≥850 V), and TO-92 thermal performance (Rth(j-l) = 60 °C/W) are critical to eliminating varistors and reducing BOM count by up to 80%.
Technical Context
The ACS108-8SA implements A.S.D.® (Advanced Static Discharge) technology to provide intrinsic overvoltage protection via controlled avalanche clamping (VCL ≥ 850 V) followed by crowbar action during inductive turn-off. Its gate-level shifter isolates digital controllers from mains-referenced switching paths.
It requires no external snubber or varistor due to built-in surge ruggedness (2 kV peak pulse per IEC 61000-4-5) and high static dV/dt immunity (≥2000 V/μs at 125 °C). Triggering uses a negative gate current (IGT ≤ 10 mA), flowing out of the G pin into the controller's ground-referenced driver.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IT(RMS) | 0.8 A RMS - supports continuous switching of low-power inductive loads (e.g., solenoids, fans) on 230 VAC mains without heatsink at Ta ≤ 64 °C. |
| VDRM / VRRM | 800 V - blocks full sine-wave mains voltage including transients up to 2 kV peak above line voltage per IEC 61000-4-5. |
| IGT | 10 mA max - enables direct drive from MCU GPIO pins with only a series resistor (e.g., 220 Ω at 3.3 V). |
| VCL | ≥850 V - provides headroom before clamping and initiates safe crowbar conduction to dissipate inductive energy without external components. |
| dV/dt immunity | ≥2000 V/μs at 125 °C - prevents false triggering from EMI or fast transients in noisy industrial environments. |
| Rth(j-l) | 60 °C/W - allows thermal coupling to shared cooling pads via common tab connection in multi-switch layouts. |
Pinout & Package
Package: TO-92 with common tab (COM pin electrically connected to package body); lead-free, halogen-free, UL94 V0 epoxy.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COM | Common reference terminal | Connected to mains neutral or earth-referenced return path; shares tab for thermal and electrical commonality across multiple switches. |
| OUT | Load output terminal | Switched AC output to load (e.g., solenoid, lamp); referenced to COM; handles full 800 V blocking and 0.8 A RMS conduction. |
| G | Gate control input | Accepts negative gate current (≤10 mA) from MCU GPIO; internal level shifter isolates logic-side driver from mains potential. |
Key Features
| Feature | Design Value |
|---|---|
| Overvoltage crowbar protection | VCL ≥ 850 V with controlled avalanche + crowbar action safely absorbs inductive turn-off energy without snubber. |
| IEC 61000-4-5 surge ruggedness | Withstands ±2 kV non-repetitive surges (10× per polarity) without degradation or external protection. |
| High noise immunity | Static dV/dt ≥ 2000 V/μs at 125 °C prevents false triggering in EMI-heavy appliance and industrial settings. |
| Direct microcontroller interface | IGT ≤ 10 mA and gate-level shifter enable single-resistor connection to 3.3 V/5 V GPIO without optocouplers or level shifters. |
| Common-tab thermal sharing | TO-92 metal tab tied to COM pin allows mounting multiple ACS switches on one heatsink or PCB copper area. |
Applications
| Appliance Solenoid Control | Industrial Fan Switching |
|---|---|
|
Use Scenario: On/off control of water valves and detergent dispensers in washing machines and dishwashers. IC Role / Device Role / Timing Role: AC switch replacing mechanical relay; triggered once per cycle at zero-crossing-equivalent timing via MCU gate signal. Use Value: Eliminates relay coil power, contact wear, and acoustic noise while maintaining 0.8 A load capability and surge immunity per IEC 61000-4-5. |
Use Scenario: Speed-controlled fan activation in HVAC control panels and industrial enclosures. IC Role / Device Role / Timing Role: Mains-connected static switch enabling phase-angle or burst-fire control of resistive-inductive fan windings. Use Value: Enables silent, wear-free operation with <10 mA gate drive and inherent clamping of back-EMF during abrupt turn-off. |
| Low-Power Motor Start/Stop | Lamp Dimming Interface |
|
Use Scenario: Start/stop sequencing of small AC motors (<100 W) in coffee makers, air purifiers, and door locks. IC Role / Device Role / Timing Role: Solid-state replacement for electromechanical contactors; driven by MCU with negative gate current pulse. Use Value: Supports 13.7 A non-repetitive surge (tp = 16.7 ms) for motor inrush, with VCL clamping preventing overvoltage failure during stall conditions. |
Use Scenario: Mains-connected dimming interface for incandescent and halogen lamps in smart lighting systems. IC Role / Device Role / Timing Role: AC switch synchronized to zero-crossing detection for smooth phase-cut dimming control. Use Value: Delivers 800 V blocking margin and 0.8 A RMS handling for 100 W lamps, with dV/dt immunity ensuring stable operation under EMI from nearby switching circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar AC switch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ACS108-6SA | 600 V VDRM/VRRM rating vs. 800 V; identical IGT (10 mA), IT(RMS) (0.8 A), and TO-92 package. | Rated for 120 VAC mains only; insufficient blocking margin for 230 VAC + surge in European/Asian markets. | Select only for 120 VAC systems where lower cost justifies reduced surge headroom. |
| ACS108-8SCTR | Same electrical specs but supplied in tape-and-reel (2000 pcs) instead of bulk (2500 pcs); identical TO-92 package and marking. | No functional difference; optimized for automated SMT assembly rather than manual or semi-automated placement. | Choose for high-volume production lines requiring reel-fed pick-and-place compatibility. |
Compared with ACS108-6SA, the -8SA adds 200 V blocking margin essential for 230 VAC surge compliance; compared with ACS108-8SCTR, the -8SA offers higher per-bulk quantity and lower setup cost for prototyping and low-volume manufacturing.
Availability
ACS108-8SA is available at Aetrix Electronics and suitable for appliance solenoid control, industrial fan switching, and low-power motor start/stop applications requiring stable component supply, long-term lifecycle support, and IEC-compliant surge resilience.
Supply support for ACS108-8SA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensing solutions for automotive, industrial, and consumer markets.
The ACS™ AC switch product line targets solid-state replacement of electromechanical relays in mains-powered appliances and controls-emphasizing intrinsic surge protection, simplified drive, and thermal integration in compact packages like TO-92.
FAQ
What is the required gate drive configuration for ACS108-8SA?
The ACS108-8SA requires a negative gate current flowing *out* of the G pin into the controller's ground-referenced output. A typical configuration uses a 220 Ω resistor between an MCU GPIO (3.3 V or 5 V) and G, with COM tied to system ground or neutral. No positive gate voltage is applied.
Can ACS108-8SA replace a standard triac in existing designs?
Yes-but only if the triac was used in quadrant II/III triggering mode and the design accommodates negative gate current drive. Unlike standard triacs, ACS108-8SA does not require snubbers or varistors, so external protection components can be removed when migrating, provided VCL (≥850 V) meets system overvoltage requirements.
How does VCL function during inductive load turn-off?
When the gate signal is removed and load current falls below holding current (IH), the ACS108-8SA enters clamping mode at ≥850 V. Energy stored in the inductance discharges linearly through the device's avalanche region until current reaches zero, after which it recovers blocking capability at the next current zero-crossing-no external components needed.
Is heatsinking required for 0.8 A RMS operation?
At ambient temperatures ≤64 °C and with a minimum copper area of 5 cm² on FR4 PCB, no external heatsink is required. The TO-92 package achieves 0.8 A RMS with Rth(j-l) = 60 °C/W; junction temperature remains within −30 to +125 °C limits. Above 64 °C ambient, derating applies per Figure 2 in DS12901.
ACS108-8SA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- ACS™/A.S.D®
- Package/Case:
- TO-226-3, TO-92-3 (TO-226AA)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Triac Type:
- Logic - Sensitive Gate
- Voltage - Off State:
- 800 V
- Current - On State (It (RMS)) (Max):
- 450 mA
- Voltage - Gate Trigger (Vgt) (Max):
- 1 V
- Current - Non Rep. Surge 50, 60Hz (Itsm):
- 13A, 13.7A
- Current - Gate Trigger (Igt) (Max):
- 10 mA
- Current - Hold (Ih) (Max):
- 10 mA
- Configuration:
- Single
- Operating Temperature:
- -30°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-92
ACS108-8SA FAQ
1.How can I place an order for ACS108-8SA through Aetrix?
Please submit a Request for Quotation (RFQ) for ACS108-8SA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for ACS108-8SA reliable?
The price and inventory of ACS108-8SA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ACS108-8SA is usually 5 days.
3.What payment methods are accepted for ACS108-8SA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ACS108-8SA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ACS108-8SA?
ACS108-8SA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ACS108-8SA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for ACS108-8SA?
For technical support, including ACS108-8SA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ACS108-8SA requirements.
6.How does Aetrix verify that ACS108-8SA is sourced from the original manufacturer or authorized distributors?
All ACS108-8SA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that ACS108-8SA meets industry standards.
7.What is the process for return or replacement of ACS108-8SA?
All ACS108-8SA units undergo pre-shipment inspection (PSI). If there is an issue with ACS108-8SA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The ACS108-8SA part is unused and in its original packaging.
Return procedure for ACS108-8SA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ACS108-8SA Tags
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